diff --git a/modules/mesh-delivery-builder/buildrun/asks.go b/modules/mesh-delivery-builder/buildrun/asks.go
index 26cc3e2c..d65d845e 100644
--- a/modules/mesh-delivery-builder/buildrun/asks.go
+++ b/modules/mesh-delivery-builder/buildrun/asks.go
@@ -1,6 +1,7 @@
 package buildrun
 
 import (
+	"cmp"
 	"context"
 	"encoding/json"
 	"errors"
@@ -34,6 +35,9 @@ type AskWaiter interface {
 
 // Asker puts asks and waits for their steps.
 type Asker struct {
+	// Name is the asker the subject names, the caller's seat name (design 47 G A-248, A-163): empty puts under the builder's
+	// name until the asker rename after the join.
+	Name      string
 	Publisher AskPublisher
 	Waiter    AskWaiter
 	// Seats finds the build module of an ask's language (design 47 G A-82).
@@ -173,8 +177,8 @@ func (k Asker) dropped(a buildstep.StepAsk, why string) {
 // PutTry is how long one publish of an ask waits for its stream's answer before it is made again (Put).
 var PutTry = 10 * time.Second
 
-// Put puts a on its stream: the seat's accept subject of its language and kind, under the builder's name as asker (design 47 G
-// §481, §600: `accept.<queue>.builder`). The put is a kept call (novox/hq ADR 0668
+// Put puts a on its stream: the seat's accept subject of its language and kind, under the asker's Name, else the builder's
+// name (design 47 G §481, §600, A-248: `accept.<queue>.builder`). The put is a kept call (novox/hq ADR 0668
 // §1, §2; issue 1966, issue 1748 note 27): it carries the ask's id as its message id, so the stream takes it once, and it
 // is made again through every transport fault (a deadline, no responders) within busretry.Bound, each try bounded by
 // PutTry, until ctx ends. A put that still meets one is an error opening `transport fault:` (TransportFault), so the key it
@@ -184,7 +188,7 @@ func (k Asker) Put(ctx context.Context, a buildstep.StepAsk) error {
 	if err != nil {
 		return err
 	}
-	subject, err := buildstep.AskSubjectBy(a.Language, a.Kind, buildstep.AskerBuilder)
+	subject, err := buildstep.AskSubjectBy(a.Language, a.Kind, cmp.Or(k.Name, buildstep.AskerBuilder))
 	if err != nil {
 		return err
 	}
diff --git a/modules/mesh-delivery-builder/buildrun/asks_test.go b/modules/mesh-delivery-builder/buildrun/asks_test.go
index fac93dbd..5f847802 100644
--- a/modules/mesh-delivery-builder/buildrun/asks_test.go
+++ b/modules/mesh-delivery-builder/buildrun/asks_test.go
@@ -44,6 +44,11 @@ func TestAnAskerPutsOnceAndReadsTheStep(t *testing.T) {
 	if len(subjects.seen) != 1 || subjects.seen[0] != "mesh.seat.node-build-go.accept."+goAsk("x").Kind+".builder" {
 		t.Fatalf("the ask was put on %v", subjects.seen)
 	}
+	// A-248: an asker that names itself puts under its own name.
+	byName := Asker{Name: "indexer", Seats: testSeats(), Publisher: subjects, Waiter: f}
+	if err := byName.Put(context.Background(), goAsk("mvl0frv18d1959")); err != nil || subjects.seen[len(subjects.seen)-1] != "mesh.seat.node-build-go.accept."+goAsk("x").Kind+".indexer" {
+		t.Fatalf("a named asker put on %v (%v)", subjects.seen, err)
+	}
 	f.Answer = func(a buildstep.StepAsk) buildstep.Step {
 		return buildstep.Step{ID: a.ID, Node: "shanks", State: buildstep.StepRefused, Reason: "go 1.27 installed"}
 	}
diff --git a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer-tools/main.go b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer-tools/main.go
index c767b78b..a584fa9b 100644
--- a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer-tools/main.go
+++ b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer-tools/main.go
@@ -316,6 +316,10 @@ func main() {
 	})...)
 	tools = append(tools, viewTools(os.Getenv, trunk.State, time.Now)...)
 	tools = append(tools, index.PendingTools(keptRead{stdio.State(index.PendingState)}, keptRead{stdio.State(index.OwnBuildStateName)}, asks, time.Now)...)
+	tools = append(tools, index.ValidationTools(asks, time.Now, func(what, why string) error {
+		_, err := acts.Record(meshhandactsclient.Request{What: what, Why: why, Cause: index.ValidateAgainTool, Verb: "validate-again"})
+		return err
+	})...)
 	tools = append(tools, index.FingerprintsTools(asks, time.Now, func(what, why string) error {
 		_, err := acts.Record(meshhandactsclient.Request{What: what, Why: why, Cause: index.FingerprintsAgainTool, Verb: "fingerprints-again"})
 		return err
diff --git a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/integration_test.go b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/integration_test.go
index 67660906..a995b7a3 100644
--- a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/integration_test.go
+++ b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/integration_test.go
@@ -22,6 +22,7 @@ import (
 
 	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-contracts/go/seats/nodebuildgo"
 	sdkstep "git.novox.be/novox/mesh-delivery/modules/mesh-delivery-sdk/buildstep"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-sdk/composer"
 
 	"github.com/nats-io/nats-server/v2/server"
 	"github.com/nats-io/nats.go"
@@ -88,6 +89,10 @@ func TestIndexerWhole(t *testing.T) { // 1238/AC2, AC10; 1585/T14, T15
 	// The forge bridge's tool bridge_merged_message (issue 1585): answers the merged message published for a merge, by
 	// repository@merge, as the bridge does; a restarted indexer holds none in memory and asks it.
 	var bridgeMessages sync.Map
+	// The build seat node-build-go's stand-in (design 47 G §712, §713): it hears the indexer's validation asks and ends each with
+	// the manifest validator's verdict; refusing names, by the commit the job runs at, the manifest a revision's change refuses.
+	var validations *standIn
+	var refusing sync.Map
 	js, ctx, candidates, _, restart := startIndexerRun(t, func(ctx context.Context, builds buildLog) {
 		// The builder's log entries of two builds' ends (ADR 0571 clause 1), as the builder appends them.
 		builds.end(t, "novox/mesh-delivery", "a", "modules/a")
@@ -115,7 +120,22 @@ func TestIndexerWhole(t *testing.T) { // 1238/AC2, AC10; 1585/T14, T15
 		if _, err := tc.Put(ctx, key, value); err != nil {
 			t.Fatal(err)
 		}
-		seedBuildModules(t, ctx, js, nil)
+		// The trunk holds the indexer's entry, taken in at an earlier commit with its own manifest; the seat git answers its go.mod, so
+		// its Go artifacts carry the Go module the validation's program is read under (§712, §676, A-263).
+		seedBuildModules(t, ctx, js, map[string]meshcatalog.CatalogEntry{index.Module: trunkIndexerEntry(t, ctx, js)})
+		if _, err := js.Conn().Subscribe("mesh.seat.git.tool.file", func(m *nats.Msg) {
+			var a git.FileInput
+			_ = json.Unmarshal(m.Data, &a)
+			answer := git.FileAnswer{Path: a.Path, Ref: a.Ref, Absent: true}
+			if a.Path == "modules/"+index.Module+"/go.mod" {
+				answer = git.FileAnswer{Path: a.Path, Ref: a.Ref, Content: "module " + index.Module + "\n"}
+			}
+			raw, _ := json.Marshal(map[string]any{"result": answer, "node": "n0"})
+			_ = m.Respond(raw)
+		}); err != nil {
+			t.Fatal(err)
+		}
+		validations = standInBuildSeat(t, ctx, js, &refusing)
 		// The node-engine's composition on n1 (process.Conn.Call's subjects): the build of the indexer that runs there.
 		answer := func(m *nats.Msg) {
 			raw, _ := json.Marshal(map[string]any{"result": map[string]any{"runs": map[string]string{"fp": *running.Load()}}, "node": "n1"})
@@ -271,6 +291,13 @@ func TestIndexerWhole(t *testing.T) { // 1238/AC2, AC10; 1585/T14, T15
 		t.Fatalf("take-in.pending.%s = %+v (said %v) within 20 s, want the revision waiting for another build than %s", m1Key, held, ok, first)
 	}
 	named := held.WaitsFor
+	// IX5 (§712): the revision was validated first, by one run ask whose job names the indexer entry's repository, path and
+	// the revision's head, and no heads; accepted, it is never asked again while it waits for the named indexer.
+	if asks := validations.asked(); len(asks) != 1 || asks[0].Run == nil || asks[0].Kind != sdkstep.AskCheck ||
+		asks[0].Run.Program.Repository != m1.Repository || asks[0].Run.Program.Dir != "modules/"+ix || asks[0].Run.Program.Commit != m1.Merge ||
+		len(asks[0].Run.Heads) != 0 || !strings.HasSuffix(asks[0].Run.Program.Package, "/cmd/mesh-judge") {
+		t.Fatalf("validation asks = %+v, want one run of the indexer's manifest validator at %s", asks, m1.Merge)
+	}
 	get := func(bucket, key string) ([]byte, bool) {
 		t.Helper()
 		if bucket == index.ModulesState { // the view of the trunk, from the newest catalog graph revision
@@ -403,6 +430,112 @@ func TestIndexerWhole(t *testing.T) { // 1238/AC2, AC10; 1585/T14, T15
 		t.Errorf("the group's first member %s was said pending as a revision of its own", g1Key)
 	}
 
+	// IX5 (§712, §713): a merge whose changed manifest gains a problem the trunk case lacks stays pending, refused naming it,
+	// said in take-in.pending; nothing of it is taken in.
+	m3 := forgemsg.Forge{Kind: forgemsg.ForgeMerged, Repository: "novox/mesh-delivery", Branch: "feat/y", Number: 13, Head: h1,
+		Merge: "3333333333333333333333333333333333333333", Root: "r0", Trees: map[string]string{"modules/a": "tree-a-3"},
+		Manifests: map[string]string{"modules/a": `{"module":"a","version":"2.0"}`}}
+	refusing.Store(m3.Merge, "a")
+	m3Key := takein.PendingKey(merged(m3))
+	if refused, ok := said(takein.TakeInPending, m3Key); !ok || !strings.Contains(refused.Refused, "a: the stand-in's problem") || refused.Failed != "" {
+		t.Fatalf("take-in.pending.%s = %+v (said %v) within 20 s, want the revision refused naming a's problem", m3Key, refused, ok)
+	}
+	if w = waits(); len(w) != 1 || w[0].Key != m3Key || w[0].Validation == nil || w[0].Validation.Accepted != 0 || len(validations.asked()) != 3 {
+		t.Fatalf("indexer_pending = %+v, asks %d: want the refused revision pending with its validation, asked once after m1 and the group", w, len(validations.asked()))
+	}
+	if raw, ok := get(index.ModulesState, "a"); !ok || strings.Contains(string(raw), m3.Merge) {
+		t.Errorf("modules.a = %s: the refused revision was taken in", raw)
+	}
+
+}
+
+// trunkIndexerEntry keeps the indexer's own manifest by its digest, accepted, and answers its trunk entry at an earlier commit.
+func trunkIndexerEntry(t *testing.T, ctx context.Context, js jetstream.JetStream) meshcatalog.CatalogEntry {
+	t.Helper()
+	raw, err := os.ReadFile("../../module.json")
+	if err != nil {
+		t.Fatal(err)
+	}
+	var m catalogue.Manifest
+	if err := json.Unmarshal(raw, &m); err != nil {
+		t.Fatal(err)
+	}
+	digest := meshcatalogclient.ManifestDigest(raw)
+	manifests, err := js.KeyValue(ctx, index.ManifestsBucket)
+	if err != nil {
+		t.Fatal(err)
+	}
+	mkey, _ := meshcatalogclient.ManifestsKey(digest)
+	mdata, _ := meshcatalogclient.EncodeManifest(meshcatalog.ManifestsByDigestValue{Module: index.Module, Manifest: string(raw)})
+	if _, err := manifests.Put(ctx, mkey, mdata); err != nil {
+		t.Fatal(err)
+	}
+	held := meshcatalog.ModulesByModuleValue{Repository: "novox/mesh-delivery", Commit: "4444444444444444444444444444444444444444", Path: "modules/" + index.Module,
+		Manifest: digest, None2: sdkstep.ToolchainNoReport}
+	e := index.CatalogEntryOf(index.Module, held, m, string(raw), graph.Node{None: held.None2})
+	for _, a := range m.Build.Artifacts {
+		e.Artifacts = append(e.Artifacts, meshcatalog.Artifact{Kind: a.Kind, Language: a.Language, Ref: index.ArtifactRefOf(index.Module, a.Name),
+			Package: &meshcatalog.ArtifactPackage{Ecosystem: index.EcosystemGo, Name: index.Module}})
+	}
+	return e
+}
+
+// standIn is the build seat node-build-go as the indexer's validation meets it: the asks it heard, oldest first.
+type standIn struct {
+	mu   sync.Mutex
+	asks []sdkstep.StepAsk
+}
+
+func (s *standIn) asked() []sdkstep.StepAsk {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return slices.Clone(s.asks)
+}
+
+// standInBuildSeat keeps the seat's check queue as a stream and hears the indexer's asks on it (accept.check.indexer): each is
+// ended at once with step-ended on the seat's family, its answer inline (A-254) the manifest validator's verdict over both cases,
+// the change case refusing the manifest refusing names for the job's commit.
+func standInBuildSeat(t *testing.T, ctx context.Context, js jetstream.JetStream, refusing *sync.Map) *standIn {
+	t.Helper()
+	subject, err := sdkstep.AskSubjectBy(sdkstep.AskGo, sdkstep.AskCheck, index.ValidationAsker)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := js.CreateStream(ctx, jetstream.StreamConfig{Name: "SEAT_NODE_BUILD_GO_CHECK", Subjects: []string{"mesh.seat.node-build-go.accept.check.>"}}); err != nil {
+		t.Fatal(err)
+	}
+	// The indexer's state inputs and its objects, where the validation's request is kept for the build seat's holder (§354).
+	if _, err := js.CreateKeyValue(ctx, jetstream.KeyValueConfig{Bucket: index.InputsBucket, History: 1}); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := js.CreateObjectStore(ctx, jetstream.ObjectStoreConfig{Bucket: catalogue.BusName(index.Module, catalogue.StateObjectsName(index.InputsState))}); err != nil {
+		t.Fatal(err)
+	}
+	s := &standIn{}
+	if _, err := js.Conn().Subscribe(subject, func(m *nats.Msg) {
+		a, err := sdkstep.DecodeStepAsk(m.Data)
+		if err != nil || a.Run == nil {
+			t.Errorf("the stand-in build seat heard what is no run ask: %v", err)
+			return
+		}
+		s.mu.Lock()
+		s.asks = append(s.asks, a)
+		s.mu.Unlock()
+		change := composer.CaseVerdict{Name: "change", Manifests: map[string]composer.ManifestRead{}}
+		if module, ok := refusing.Load(a.Run.Program.Commit); ok {
+			change.Manifests[module.(string)] = composer.ManifestRead{Refused: "the stand-in's problem"}
+		}
+		verdict, _ := json.Marshal(composer.Verdict{V: 1, Cases: []composer.CaseVerdict{change, {Name: judge.TrunkCase, Manifests: map[string]composer.ManifestRead{}}}})
+		answer, _ := json.Marshal(sdkstep.RunAnswer{Built: true, Exit: 0, Output: verdict})
+		end, _ := json.Marshal(sdkstep.StepEnded{V: 1, ID: a.ID, Ask: a.ID, Asker: index.ValidationAsker, Node: "n1", Outcome: sdkstep.OutcomePassed,
+			Output: string(answer), At: time.Now().UTC()})
+		if _, err := js.Publish(ctx, nodebuildgo.SubjectStepEnded("n1"), end); err != nil {
+			t.Errorf("the stand-in build seat could not say step-ended: %v", err)
+		}
+	}); err != nil {
+		t.Fatal(err)
+	}
+	return s
 }
 
 // jsSource is a bucket as a views.Source.
@@ -665,7 +798,7 @@ func startIndexerRun(t *testing.T, put func(context.Context, buildLog), before .
 	// The shared events stream: the indexer's ordinary events and the assigner's views events (ADR 0635 §5).
 	if _, err := js.CreateStream(ctx, jetstream.StreamConfig{Name: "EVENTS", Subjects: []string{"mesh.mod.*.event.>", "mesh.seat.mesh-catalog.event.>", "mesh.seat.mesh-delivery.event.>", "mesh.seat.mesh-delivery-checker.event.>",
 		"mesh.seat.mesh-conditions.event.>", "mesh.seat.operator-channel.event.>", "mesh.seat.go-package-registry.event.>", "mesh.seat.npm-package-registry.event.>",
-		"mesh.seat.mesh-module-assigner.event.>"}}); err != nil { // not the seats kept in streams of their own (wanted and running, above)
+		"mesh.seat.mesh-module-assigner.event.>", "mesh.seat.node-build-go.event.>"}}); err != nil { // not the seats kept in streams of their own (wanted and running, above)
 		t.Fatal(err)
 	}
 	// The indexer's own stream of its findings' events (design 47 G §383), which its finding writer says into (A-30).
@@ -1444,7 +1577,8 @@ func serveAssignerAssignments(t *testing.T, ctx context.Context, js jetstream.Je
 		t.Fatal(err)
 	}
 	if _, err := js.CreateOrUpdateConsumer(ctx, "EVENTS", jetstream.ConsumerConfig{Durable: "n1_mesh-delivery-indexer", AckPolicy: jetstream.AckExplicitPolicy,
-		FilterSubjects: []string{"mesh.mod." + assignerHolderModule + ".event.views.>", "mesh.seat.mesh-delivery.event.>"}}); err != nil {
+		// and the build seat's step-ended the manifest's consumes names (design 47 G §713: the end of a validation ask).
+		FilterSubjects: []string{"mesh.mod." + assignerHolderModule + ".event.views.>", "mesh.seat.mesh-delivery.event.>", nodebuildgo.SubjectStepEndedAll}}); err != nil {
 		t.Fatal(err)
 	}
 	em := views.Emitter{Owner: assignerHolderModule, Subject: process.Account{Node: "n1", Module: assignerHolderModule}.EventSubject,
diff --git a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/main.go b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/main.go
index 8b0e1394..6df5cc56 100644
--- a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/main.go
+++ b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/main.go
@@ -476,7 +476,9 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 		// The take-in step (ADR 0633): its state pending and its stream take-in, both this delivery's, bound when they appear;
 		// until then every merge is taken in at once, as before.
 		Pending:   awaitedStore{b: process.AwaitBucket(ctx, js, conn, index.PendingBucket, "no merge is held for the indexer its revision names: each is taken in at once", logger.Printf)},
-		SayTakeIn: sayTakeIn(js, cred)}
+		SayTakeIn: sayTakeIn(js, cred),
+		// The validation's run ask (design 47 G §713, A-247, A-248), put under the indexer's own asker.
+		ValidationAsks: buildrun.Asker{Name: index.ValidationAsker, Publisher: buildrun.JetStreamAsks{JS: js}}}
 	// The registrations and the changes that wait for their warrant (design 47 G §2, §667): their states are bound when they
 	// appear; a warrant is heard on the router's decided event for this module, below.
 	registry := newRegistry(js, conn, cred, calls.Call,
diff --git a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/takein.go b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/takein.go
index e72897a0..dde180b0 100644
--- a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/takein.go
+++ b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/takein.go
@@ -28,6 +28,7 @@ type takerIn interface {
 	NamedDrop(ctx context.Context, fingerprint, member, by, why string) index.TakenIn
 	Unpin(ctx context.Context, revision, record, by, why string) index.TakenIn
 	DropRunByHand(ctx context.Context, run, by, why string) index.TakenIn
+	ValidateAgainByHand(ctx context.Context, key, by, why string) index.TakenIn
 	RegistryAct(ctx context.Context, a index.TakeInAsk) index.TakenIn
 }
 
@@ -69,6 +70,9 @@ func takenIn(ctx context.Context, ix takerIn, kv jetstream.KeyValue, e jetstream
 	} else if a.Merge != "" {
 		asked, r = "hand take-in of a merge", ix.TakeInMerge(ctx, a.MergeRepository, a.Merge, a.Sequence, a.By, a.Why)
 		a.Module = r.Module
+	} else if a.Pending != "" && a.ValidateAgain {
+		asked, r = "validation asked again", ix.ValidateAgainByHand(ctx, a.Pending, a.By, a.Why)
+		a.Module = a.Pending
 	} else if a.Pending != "" && a.Drop {
 		asked, r = "drop of a pending merge", ix.DropPending(ctx, a.Pending, a.By, a.Why, a.Abandon)
 		a.Module = a.Pending
diff --git a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/versions.go b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/versions.go
index cb5dc56d..1c473918 100644
--- a/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/versions.go
+++ b/modules/mesh-delivery-indexer/cmd/mesh-delivery-indexer/versions.go
@@ -7,6 +7,8 @@ import (
 	"sync/atomic"
 	"time"
 
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-sdk/buildstep"
+
 	"github.com/nats-io/nats.go"
 	"github.com/nats-io/nats.go/jetstream"
 
@@ -121,6 +123,15 @@ func heardStepEnded(ctx context.Context, ix *index.Indexer, m jetstream.Msg, log
 		_ = m.Ack()
 		return
 	}
+	// The end of a validation ask resumes its pending revision (design 47 G §713); its own fault is given again by the bus.
+	var end buildstep.StepEnded
+	if err := json.Unmarshal(m.Data(), &end); err == nil {
+		if err := ix.HearValidationEnded(ctx, end); err != nil {
+			logf("take-in: the end of the validation ask %s is not taken in, so the bus gives it again: %v", end.Ask, err)
+			_ = m.Nak()
+			return
+		}
+	}
 	if err := ix.HearInputEnded(ctx, e); err != nil {
 		logf("inputs: the input of the ask %s could not be deleted, so the bus gives it again: %v", e.Ask, err)
 		_ = m.Nak()
diff --git a/modules/mesh-delivery-indexer/internal/index/artifacts.go b/modules/mesh-delivery-indexer/internal/index/artifacts.go
index e12e23e1..e48da124 100644
--- a/modules/mesh-delivery-indexer/internal/index/artifacts.go
+++ b/modules/mesh-delivery-indexer/internal/index/artifacts.go
@@ -13,7 +13,7 @@ import (
 
 // Each entry carries its artifacts' package names (design 47 G §676, §491, §478, §504, §412): at take-in the indexer reads
 // each artifact's package name from the revision's own files at the artifact's path, the module of its go.mod for a Go
-// package, the name of its package.json for an npm package, the module's and the artifact's names joined by / for an image artifact (§694), and writes it into
+// package and for a Go bundle (A-263), the name of its package.json for an npm package, the module's and the artifact's names joined by / for an image artifact (§694), and writes it into
 // the entry's artifact as package, {ecosystem, name}. The manifest validator judges §491 from these fields.
 
 // Package ecosystems of an artifact's package (§676).
@@ -47,13 +47,16 @@ func (ix *Indexer) withArtifacts(ctx context.Context, e meshcatalog.CatalogEntry
 
 // packageOf is the package name of artifact a of the entry e: read through the forge at the entry's commit, kept per
 // repository, commit, path and artifact so a later entry of the same commit reads nothing; nil for an artifact that names
-// none (a program, an archive) or whose name cannot be read now.
+// none (a program or an archive not built from a Go module) or whose name cannot be read now.
 func (ix *Indexer) packageOf(ctx context.Context, e meshcatalog.CatalogEntry, a catalogue.Artifact) *meshcatalog.ArtifactPackage {
-	switch a.Kind {
-	case catalogue.ArtifactPackage:
-	case catalogue.ArtifactImage:
+	switch {
+	case a.Kind == catalogue.ArtifactPackage:
+	case a.Kind == catalogue.ArtifactImage:
 		// An image's package name is its module's name and its artifact's joined by `/`, read from no file (§694).
 		return &meshcatalog.ArtifactPackage{Ecosystem: EcosystemImage, Name: e.Module + "/" + a.Name}
+	case a.Language == "go":
+		// A Go artifact of any kind, a bundle too, is built from the Go module its go.mod names (design 47 G A-263): the manifest
+		// validator's program is read under it (§712).
 	default:
 		return nil
 	}
diff --git a/modules/mesh-delivery-indexer/internal/index/candidates.go b/modules/mesh-delivery-indexer/internal/index/candidates.go
index a35e5c54..f33619f1 100644
--- a/modules/mesh-delivery-indexer/internal/index/candidates.go
+++ b/modules/mesh-delivery-indexer/internal/index/candidates.go
@@ -222,6 +222,12 @@ type Indexer struct {
 	Pending Store
 	// SayTakeIn publishes a take-in event (take-in.pending, take-in.taken; ADR 0633 §5); nil says none.
 	SayTakeIn func(ctx context.Context, t takein.TakeIn) error
+	// ValidationAsks puts the validation's run ask (design 47 G §713, A-247: buildrun.Asker, named as the indexer's asker,
+	// A-248); nil validates nothing, and a revision is taken in as before.
+	ValidationAsks ValidationAsks
+	// ReadStepOutput reads a step-ended's output object, where the build seat keeps an answer too large for the event
+	// (A-247); nil reads none, and such an answer could not validate.
+	ReadStepOutput func(ctx context.Context, object string) ([]byte, error)
 	// Runs is the state runs: the runs on request the indexer holds a candidate for (runcandidates.go, A-174); nil keeps none.
 	Runs      Store
 	runMu     sync.Mutex // one run event at a time (runcandidates.go)
diff --git a/modules/mesh-delivery-indexer/internal/index/catalog_graph_test.go b/modules/mesh-delivery-indexer/internal/index/catalog_graph_test.go
index e2502b19..5cfaf763 100644
--- a/modules/mesh-delivery-indexer/internal/index/catalog_graph_test.go
+++ b/modules/mesh-delivery-indexer/internal/index/catalog_graph_test.go
@@ -33,11 +33,12 @@ func TestAnEntryCarriesItsManifestWholeAndTheDigestOfItsBytes(t *testing.T) {
 }
 
 // Design 47 G §676: at take-in the entry's artifacts carry the package name read from the revision's own files at the
-// artifact's path: the module of a go.mod, the name of a package.json.
+// artifact's path: the module of a go.mod, the name of a package.json; a Go bundle the module of its go.mod (A-263).
 func TestAnEntryCarriesItsArtifactsPackageNames(t *testing.T) {
 	ix := &Indexer{ReadFile: func(_ context.Context, repository, sha, path string) ([]byte, error) {
 		files := map[string]string{
 			"mods/m/go/go.mod":       "module git.example/m/go\n\ngo 1.26\n",
+			"mods/m/go.mod":          "module git.example/m\n",
 			"mods/m/js/package.json": `{"name":"@example/m"}`,
 		}
 		if repository != "r" || sha != "c1" {
@@ -53,6 +54,7 @@ func TestAnEntryCarriesItsArtifactsPackageNames(t *testing.T) {
 		{Name: "jspkg", Kind: catalogue.ArtifactPackage, Language: "typescript", Paths: []string{"js"}},
 		{Name: "img", Kind: catalogue.ArtifactImage},
 		{Name: "prog", Kind: "bundle", Language: "go"},
+		{Name: "web", Kind: "bundle", Language: "typescript"},
 	}}}
 	e := ix.withArtifacts(context.Background(), meshcatalog.CatalogEntry{Module: "m", Repository: "r", Path: "mods/m", Commit: "c1"}, m)
 	got := map[string]string{}
@@ -63,7 +65,8 @@ func TestAnEntryCarriesItsArtifactsPackageNames(t *testing.T) {
 		}
 		got[a.Ref] = name
 	}
-	want := map[string]string{"m:gopkg": "go git.example/m/go", "m:jspkg": "npm @example/m", "m:img": "image m/img", "m:prog": "none"}
+	want := map[string]string{"m:gopkg": "go git.example/m/go", "m:jspkg": "npm @example/m", "m:img": "image m/img",
+		"m:prog": "go git.example/m", "m:web": "none"} // A-263: a Go bundle carries the Go module its go.mod names
 	if !reflect.DeepEqual(got, want) {
 		t.Errorf("artifacts' packages %v, want %v (§676)", got, want)
 	}
diff --git a/modules/mesh-delivery-indexer/internal/index/pending.go b/modules/mesh-delivery-indexer/internal/index/pending.go
index ae1aee31..15a81ecf 100644
--- a/modules/mesh-delivery-indexer/internal/index/pending.go
+++ b/modules/mesh-delivery-indexer/internal/index/pending.go
@@ -98,6 +98,8 @@ type Pending struct {
 	// Held is why a ready merge is not taken in although its revision names this build: objects full (HeldObjectsFull),
 	// until room is said (RoomAgain).
 	Held string `json:"held,omitempty"`
+	// Validation is the revision's validation (design 47 G §713, A-247), on the revision's newest value alone.
+	Validation *takein.Validation `json:"validation,omitempty"`
 }
 
 // PendingEntry is one key of the pending state as read: its key, revision, value and the merged message decoded. For a
@@ -773,6 +775,9 @@ func (ix *Indexer) evaluate(ctx context.Context, own string, start bool) (Applie
 	if len(lost) > 0 {
 		return Applied{}, ix.waitingLine(w), ix.holdLost(ctx, w.Ready, lost, reasons, unread)
 	}
+	if wait, words, err := ix.validationGate(ctx, ready, own); wait || err != nil {
+		return Applied{}, words, err
+	}
 	names, dry, err := ix.computeOver(ctx, ready)
 	if err != nil {
 		return Applied{}, "", err
@@ -904,6 +909,7 @@ func (ix *Indexer) dry() *dryRun {
 	x := &Indexer{Manifests: ix.Manifests, Packages: ix.Packages, JudgeID: ix.JudgeID, Files: ix.Files, GoSum: ix.GoSum,
 		GoMod: ix.GoMod, Now: ix.Now, Builds: ix.Builds, Named: ix.Named, Trunk: ix.Trunk, Read: ix.Read, Contains: ix.Contains,
 		ReadOpen: nil, OwnBuild: nil, Message: ix.Message, SayRefused: nil, SayAccepted: nil, SayTakeIn: nil, Pending: nil,
+		ValidationAsks: nil, ReadStepOutput: nil, // a dry run asks no validation (§713)
 		// The registry milestone's fields: what a take-in would write on the bus stays out of a dry run, so the states of the
 		// requirements, findings, seat definitions, holds and their bounds are not overlaid, nothing is said, and no hold is
 		// weighed (Holds and Counted nil hold nothing); ReadFile only reads.
@@ -1332,6 +1338,9 @@ func waitOf(entries []PendingEntry, what, behind string) takein.PendingWait {
 		if e.Value.Refused != "" {
 			pw.Refused = e.Value.Refused
 		}
+		if e.Value.Validation != nil {
+			pw.Validation = e.Value.Validation
+		}
 		if e.Value.Said != "" && e.Value.SaidAt.After(pw.SaidAt) {
 			pw.Said, pw.SaidAt = "take-in."+e.Value.SaidKind, e.Value.SaidAt
 		}
diff --git a/modules/mesh-delivery-indexer/internal/index/pending_test.go b/modules/mesh-delivery-indexer/internal/index/pending_test.go
index a3e072a5..04c22a84 100644
--- a/modules/mesh-delivery-indexer/internal/index/pending_test.go
+++ b/modules/mesh-delivery-indexer/internal/index/pending_test.go
@@ -1131,7 +1131,7 @@ func TestTakeIn(t *testing.T) { // 1585/T3-T13 (ADR 0633)
 		for _, f := range []string{"Store", "Modules", "Manifests", "Predefined", "ConfigCandidates", "Taken", "Verdicts", "OldSections", "Unjudged",
 			"JudgeID", "SayRefused", "SayAccepted", "Packages", "Graph", "Files", "GoSum", "GoMod", "Now", "Builds", "Named", "Trunk",
 			"Read", "Contains", "Logf", "ReadOpen", "OwnBuild", "Message", "Pending", "SayTakeIn",
-			"Requirements", "Findings", "SeatDefinitions", "ReadFile", "SaySeatDefinition", "Runs", "OwnBuildState", "Heard", "Placement", "RunningWhole", "Revisions", "SayCatalogRevision", "SayFill", "EntryIndex", "NamedSets", "Registry", "SeedModules", "Versions", "SayVersionReleased", "SayVersionsFilled", "Inputs", "InputObjects", "BuildEdges", "Pins", "PinsPending"} {
+			"Requirements", "Findings", "SeatDefinitions", "ReadFile", "SaySeatDefinition", "Runs", "OwnBuildState", "Heard", "Placement", "RunningWhole", "Revisions", "SayCatalogRevision", "SayFill", "EntryIndex", "NamedSets", "Registry", "SeedModules", "Versions", "SayVersionReleased", "SayVersionsFilled", "Inputs", "InputObjects", "BuildEdges", "Pins", "PinsPending", "ValidationAsks", "ReadStepOutput"} {
 			named[f] = true
 		}
 		ty := reflect.TypeOf(Indexer{})
diff --git a/modules/mesh-delivery-indexer/internal/index/pending_tools.go b/modules/mesh-delivery-indexer/internal/index/pending_tools.go
index 366654eb..c27abaa7 100644
--- a/modules/mesh-delivery-indexer/internal/index/pending_tools.go
+++ b/modules/mesh-delivery-indexer/internal/index/pending_tools.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"strings"
 	"time"
 
 	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-indexer/takein"
@@ -111,3 +112,33 @@ func PendingTools(pending, ownBuild Store, ask func(key string, value []byte) (T
 			Run: merge},
 	}
 }
+
+// ValidationTools is indexer_validate_again (class act, design 47 G §713): the tools bundle writes an ask in takeins and the
+// indexer asks the revision's validation again; record says the hand act in the hand-act log before it is asked.
+func ValidationTools(ask func(key string, value []byte) (TakeInAsk, error), now func() time.Time, record func(what, why string) error) []stdio.Tool {
+	return []stdio.Tool{{Name: ValidateAgainTool,
+		Description: "Ask again the validation of a pending revision that could not validate (design 47 G §712, §713): the manifest " +
+			"validator's run on the build seat node-build-go ended could not run, exited other than 0, or answered not both cases. " +
+			"The revision is asked under its next try; the answer says the validation's state (the ask, its try, accepted, refused, " +
+			"or why it could not validate). A revision accepted, refused or whose ask is out is asked nothing: a refusal is asked " +
+			"again only by a later merge of its branch. A hand act, recorded through mesh-hand-acts before it is asked. " +
+			"indexer_pending names the keys and shows the validation whole.",
+		Input: map[string]any{"type": "object", "required": []string{"key", "why"}, "properties": map[string]any{
+			"key": map[string]any{"type": "string", "description": "the revision's wait key, m.<sequence>, as indexer_pending names it"},
+			"why": map[string]any{"type": "string", "description": "why it is asked again, in plain words"}}},
+		Run: func(args map[string]any) (any, error) {
+			str := func(k string) string { s, _ := args[k].(string); return s }
+			key, value, err := NewValidateAgainAsk(str("key"), str("why"), stdio.CallerOf(args), now())
+			if err != nil {
+				return nil, err
+			}
+			if err := record("asked the validation of the pending revision "+strings.TrimSpace(str("key"))+" again by hand", strings.TrimSpace(str("why"))); err != nil {
+				return nil, fmt.Errorf("the hand act was not recorded through mesh-hand-acts, so nothing was asked: %w", err)
+			}
+			a, err := ask(key, value)
+			if err != nil {
+				return nil, err
+			}
+			return a.Result, nil
+		}}}
+}
diff --git a/modules/mesh-delivery-indexer/internal/index/takein.go b/modules/mesh-delivery-indexer/internal/index/takein.go
index 7e581059..632a35fb 100644
--- a/modules/mesh-delivery-indexer/internal/index/takein.go
+++ b/modules/mesh-delivery-indexer/internal/index/takein.go
@@ -52,6 +52,9 @@ type TakeInAsk struct {
 	// Abandon, with Drop, drops a pending merge no later merge covers (ADR 0633 §5 asks a later merge; issue 1966, ADR
 	// 0668 §5): the hand act says why it is abandoned all the same.
 	Abandon bool `json:"abandon,omitempty"`
+	// ValidateAgain, with Pending, asks the validation of the revision under that key again (indexer_validate_again, design 47
+	// G §713): one that could not validate.
+	ValidateAgain bool `json:"validate-again,omitempty"`
 	// Merge asks the merge of MergeRepository at this commit to be taken in by hand (indexer_take_in_merge): its merged message
 	// is asked of the forge bridge and run through the take-in as a delivered one, under its stream sequence Sequence.
 	Merge           string `json:"merge,omitempty"`
@@ -165,6 +168,20 @@ func NewMergeAsk(repository, merge string, sequence uint64, why, by string, at t
 	return "merge." + merge, data, err
 }
 
+// NewValidateAgainAsk is the value indexer_validate_again writes: its key in takeins, `pending.validate-again.<key>`, and the
+// value. key is a revision's wait key, m.<sequence>, as indexer_pending names it.
+func NewValidateAgainAsk(key, why, by string, at time.Time) (string, []byte, error) {
+	key = strings.TrimSpace(key)
+	if !strings.HasPrefix(key, "m.") {
+		return "", nil, errors.New("name the revision whose validation is asked again by its key, m.<sequence>, as indexer_pending names it")
+	}
+	if strings.TrimSpace(why) == "" {
+		return "", nil, errors.New("say why (why): a hand act is recorded through mesh-hand-acts")
+	}
+	data, err := json.Marshal(TakeInAsk{V: 1, Pending: key, ValidateAgain: true, Why: strings.TrimSpace(why), By: by, At: at.UTC()})
+	return "pending.validate-again." + key, data, err
+}
+
 // NewPendingAsk is the value indexer_take_in_pending (drop false) or indexer_drop_pending (drop true) writes: its key
 // in takeins, `pending.<take-in|drop>.<key>`, and the value. key is a wait's key as indexer_pending names it, for a
 // drop one pending merge's; abandon drops one no later merge covers.
diff --git a/modules/mesh-delivery-indexer/internal/index/validate.go b/modules/mesh-delivery-indexer/internal/index/validate.go
index a394aa1e..0fbf3bdc 100644
--- a/modules/mesh-delivery-indexer/internal/index/validate.go
+++ b/modules/mesh-delivery-indexer/internal/index/validate.go
@@ -25,9 +25,9 @@ const (
 	// validationProgram is the manifest validator's program, by its directory under the indexer entry's Go module: the indexer's
 	// own code, so no repository or module name is fixed here (ADR 0666 §5).
 	validationProgram = "cmd/mesh-judge"
-	// validationAsker is the asker the ask is put under. A-232 names the indexer's seat name mesh-catalog; the ask code still
+	// ValidationAsker is the asker the ask is put under (buildrun.Asker.Name, A-248). A-232 names the indexer's seat name mesh-catalog; the ask code still
 	// names askers by their nicknames until the asker rename after the join (A-163), so this is `indexer` until then.
-	validationAsker = "indexer"
+	ValidationAsker = "indexer"
 	// validationCatalogSeat is the seat the indexer entry claims.
 	validationCatalogSeat = "mesh-catalog"
 	// The cases of the request, as the manifest validator names them.
@@ -122,23 +122,62 @@ func placeKey(repository, path string) string {
 	return strings.ToLower(trunk.RepositoryName(repository)) + " " + path
 }
 
-// revisionDefinitions are the seat definitions the merges' trees carry, raw (§712 `seats`).
+// revisionDefinitions are the validation's seat definitions, raw (§712 `seats`, A-241): the branch's revision's seat
+// definitions with the definitions the merges' trees carry laid over them, so a revision that touches no definition is still
+// judged against the whole seat list. A revision's own definitions are not kept yet (A-234), so the revision's are the
+// trunk's, read from the state seat-definitions as the verb seat-definitions answers them.
 func (ix *Indexer) revisionDefinitions(ctx context.Context, ready []PendingEntry) ([]json.RawMessage, error) {
-	defs, err := ix.revisionSeatDefinitions(ctx, ready)
+	defs, err := ix.trunkDefinitions(ctx)
 	if err != nil {
 		return nil, err
 	}
-	var out []json.RawMessage
-	for _, seat := range slices.Sorted(maps.Keys(defs)) {
-		raw, err := json.Marshal(defs[seat])
+	merged, err := ix.revisionSeatDefinitions(ctx, ready)
+	if err != nil {
+		return nil, err
+	}
+	for seat, d := range merged {
+		raw, err := json.Marshal(d)
 		if err != nil {
 			return nil, fmt.Errorf("the definition of %s: %w", seat, err)
 		}
-		out = append(out, raw)
+		defs[seat] = raw
+	}
+	var out []json.RawMessage
+	for _, seat := range slices.Sorted(maps.Keys(defs)) {
+		out = append(out, defs[seat])
 	}
 	return out, nil
 }
 
+// trunkDefinitions are the trunk's seat definitions of the state seat-definitions, raw, by seat: every `<seat>.trunk` entry
+// that holds a definition; none where the indexer keeps no such state.
+func (ix *Indexer) trunkDefinitions(ctx context.Context) (map[string]json.RawMessage, error) {
+	defs := map[string]json.RawMessage{}
+	if ix.SeatDefinitions == nil {
+		return defs, nil
+	}
+	keys, err := ix.SeatDefinitions.Keys(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("the %s state cannot be listed: %w", SeatDefinitionsState, err)
+	}
+	for _, key := range keys {
+		seat, ok := strings.CutSuffix(key, "."+SourceTrunk)
+		if !ok || strings.HasPrefix(key, outOfStepPrefix) {
+			continue
+		}
+		v, _, found, err := ix.SeatDefinitions.Get(ctx, key)
+		if err != nil {
+			return nil, fmt.Errorf("%s.%s cannot be read: %w", SeatDefinitionsState, key, err)
+		}
+		var e SeatDefinitionEntry
+		if !found || json.Unmarshal(v, &e) != nil || e.Digest == "" || len(e.Definition) == 0 {
+			continue // an entry that holds no definition is no seat of the list
+		}
+		defs[seat] = e.Definition
+	}
+	return defs, nil
+}
+
 // validationJob is the run of the manifest validator for the request (§712): the program cmd/mesh-judge under the Go module
 // the indexer entry's Go artifact names, at the entry's path, built at head, the revision's head of the entry's repository; no
 // heads and no arguments; the input the request's bytes, served by the seat mesh-catalog's verb input.
diff --git a/modules/mesh-delivery-indexer/internal/index/validate_test.go b/modules/mesh-delivery-indexer/internal/index/validate_test.go
index d99a3358..5926cc31 100644
--- a/modules/mesh-delivery-indexer/internal/index/validate_test.go
+++ b/modules/mesh-delivery-indexer/internal/index/validate_test.go
@@ -1,11 +1,14 @@
 package index
 
 import (
+	"context"
 	"encoding/json"
+	"reflect"
 	"strings"
 	"testing"
 
 	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-contracts/go/seats/meshcatalog"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-forge-bridge/forgemsg"
 	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-sdk/buildstep"
 	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-sdk/composer"
 
@@ -72,3 +75,56 @@ func TestValidationRefusesWhatTheRevisionCauses(t *testing.T) {
 		t.Errorf("no indexer entry: %v", err)
 	}
 }
+
+// The validation's seats are the branch's revision's seat definitions with the merges' changed ones laid over them (A-241): a
+// revision that touches no definition is judged against the whole seat list, and a merge's definition replaces its seat's.
+func TestValidationSeatsAreTheRevisionsWithTheMergesOver(t *testing.T) {
+	ctx := context.Background()
+	defs := newMem()
+	for seat, raw := range map[string]string{"node-engine": `{"seat":"node-engine","verbs":[{"name":"old"}]}`, "git": `{"seat":"git"}`} {
+		v, _ := json.Marshal(SeatDefinitionEntry{Seat: seat, Source: SourceTrunk, Digest: "d-" + seat, Definition: json.RawMessage(raw)})
+		defs.put(SeatDefinitionKey(seat, SourceTrunk, "", 0), v)
+	}
+	v, _ := json.Marshal(SeatDefinitionEntry{Seat: "pulled", Source: SourcePull, Pull: 3, Digest: "d", Definition: json.RawMessage(`{"seat":"pulled"}`)})
+	defs.put(SeatDefinitionKey("pulled", SourcePull, "r", 3), v)
+	ix := &Indexer{SeatDefinitions: defs}
+	seatsOf := func(raws []json.RawMessage) map[string]string {
+		out := map[string]string{}
+		for _, raw := range raws {
+			var d struct {
+				Seat  string `json:"seat"`
+				Verbs []struct {
+					Name string `json:"name"`
+				} `json:"verbs"`
+			}
+			if err := json.Unmarshal(raw, &d); err != nil {
+				t.Fatal(err)
+			}
+			out[d.Seat] = ""
+			if len(d.Verbs) > 0 {
+				out[d.Seat] = d.Verbs[0].Name
+			}
+		}
+		return out
+	}
+	got, err := ix.revisionDefinitions(ctx, nil)
+	if err != nil || !reflect.DeepEqual(seatsOf(got), map[string]string{"node-engine": "old", "git": ""}) {
+		t.Errorf("a revision touching no definition: %v (%v), want the trunk's whole list and no pull request's", seatsOf(got), err)
+	}
+	const contracts = "modules/seat-contracts"
+	f := forgemsg.Forge{Repository: "r", Merge: strings.Repeat("c", 40), Manifests: map[string]string{
+		contracts: `{"module":"seat-contracts","version":"1.0","build":{"artifacts":[{"name":"go-seats","kind":"package","language":"go","paths":["go"],"series":"0.1","generated-from":"."}]}}`}}
+	ix.Files = func(_ context.Context, _, _ string, dirs []string) (map[string]map[string]string, error) {
+		return map[string]map[string]string{dirs[0]: {"node-engine/seat.json": "1"}}, nil
+	}
+	ix.ReadFile = func(_ context.Context, _, _, p string) ([]byte, error) {
+		if p == contracts+"/seats/node-engine/seat.json" {
+			return []byte(`{"format":1,"seat":"node-engine","scope":"node","grain":"seat-list","decision":"d","domain":"Core","verbs":[{"name":"new"}]}`), nil
+		}
+		return nil, nil
+	}
+	got, err = ix.revisionDefinitions(ctx, []PendingEntry{{Forge: f}})
+	if err != nil || !reflect.DeepEqual(seatsOf(got), map[string]string{"node-engine": "new", "git": ""}) {
+		t.Errorf("a merge changing a definition: %v (%v), want its definition over the trunk's and the rest kept", seatsOf(got), err)
+	}
+}
diff --git a/modules/mesh-delivery-indexer/internal/index/validation_wait.go b/modules/mesh-delivery-indexer/internal/index/validation_wait.go
new file mode 100644
index 00000000..5e9c7f1e
--- /dev/null
+++ b/modules/mesh-delivery-indexer/internal/index/validation_wait.go
@@ -0,0 +1,340 @@
+package index
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-sdk/buildstep"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-sdk/composer"
+
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-indexer/takein"
+)
+
+// The pending revision's wait for its validation (design 47 G §713, A-232, A-247): the take-in puts the run ask of §712, writes
+// `validation` on the revision's newest pending value and ends there; the build seat's step-ended of that ask, heard through the
+// indexer's own durable consumer, resumes it: accepted takes the revision in as before, refused keeps it pending with `refused`,
+// and an end that could not validate keeps it pending with `failed`, asked again by a later merge of the branch or by hand.
+
+// ValidationAsks puts a run ask on the build seat (buildrun.Asker).
+type ValidationAsks interface {
+	Put(ctx context.Context, a buildstep.StepAsk) error
+}
+
+// newestOfRevision is the index in ready of the revision's newest merge, the value that carries `validation` (A-247).
+func newestOfRevision(ready []PendingEntry) int {
+	n := 0
+	for i, e := range ready {
+		if e.Value.Seq > ready[n].Value.Seq {
+			n = i
+		}
+	}
+	return n
+}
+
+// branchOfRevision is the watched branch the revision's merges landed on, its newest merged message's base (design 47 G §714);
+// a message that names none is the trunk's. A pending value's own branch is its pull request's, never the branch validated.
+func branchOfRevision(ready []PendingEntry) string {
+	if base := ready[newestOfRevision(ready)].Forge.Base; base != "" {
+		return base
+	}
+	return TrunkBranch
+}
+
+// validationGate says whether the ready revision waits for its validation (§713): it goes on to the take-in once its newest
+// value's validation was accepted at that value's sequence; it waits while its ask is out, while it is refused, and while it
+// could not validate; otherwise it puts a new ask, the next try, and waits. Without an asker nothing is validated.
+func (ix *Indexer) validationGate(ctx context.Context, ready []PendingEntry, own string) (bool, string, error) {
+	if ix.ValidationAsks == nil {
+		return false, "", nil
+	}
+	newest := ready[newestOfRevision(ready)]
+	seq := newest.Value.Seq
+	if v := newest.Value.Validation; v != nil && v.Seq == seq {
+		switch {
+		case v.Accepted == seq:
+			return false, "", nil
+		case v.Failed != "":
+			return true, fmt.Sprintf("the validation of the revision at %d could not validate: %s", seq, v.Failed), nil
+		case newest.Value.Refused != "":
+			return true, fmt.Sprintf("the revision at %d is refused: %s", seq, newest.Value.Refused), nil
+		case v.Ask != "":
+			return true, fmt.Sprintf("the revision at %d waits for its validation, the ask %s", seq, v.Ask), nil
+		}
+	}
+	return true, "", ix.askValidation(ctx, ready, own)
+}
+
+// askValidation puts the revision's validation ask (§712) and writes it on its newest value, the try after every earlier try
+// of the revision; an older value's validation goes (A-247: on the newest alone). A request or job that cannot be made could not
+// validate: it is written as `failed`, said, and no ask is put.
+func (ix *Indexer) askValidation(ctx context.Context, ready []PendingEntry, own string) error {
+	n := newestOfRevision(ready)
+	newest := ready[n]
+	try := 0
+	for _, e := range ready {
+		if v := e.Value.Validation; v != nil && v.Try > try {
+			try = v.Try
+		}
+	}
+	v := &takein.Validation{Seq: newest.Value.Seq, Try: try + 1, Asked: ix.now()}
+	branch := branchOfRevision(ready)
+	ask := buildstep.StepAsk{ID: buildstep.NewID(), Kind: buildstep.AskCheck, Language: buildstep.AskGo, Asker: ValidationAsker, At: ix.now().UTC()}
+	req, entry, err := ix.validationRequest(ctx, branch, ready)
+	var raw []byte
+	if err == nil {
+		raw, err = json.Marshal(req)
+	}
+	var job buildstep.RunJob
+	if err == nil {
+		job, err = validationJob(entry, revisionHead(ready, entry.Repository, entry.Commit), branch, v.Seq, raw)
+	}
+	if err == nil {
+		v.Input, err = ix.KeepInput(ctx, ask.ID, raw)
+	}
+	if err != nil {
+		v.Failed = "the validation could not be asked: " + err.Error()
+	} else {
+		v.Ask, ask.Run = ask.ID, &job
+	}
+	if err := ix.writeValidation(ctx, ready, n, v, own); err != nil {
+		return err
+	}
+	if v.Failed != "" {
+		ix.sayValidation(ctx, ready, v)
+		return nil
+	}
+	if err := ix.ValidationAsks.Put(ctx, ask); err != nil {
+		return fmt.Errorf("the validation ask %s of the revision at %d could not be put: %w", ask.ID, v.Seq, err)
+	}
+	ix.logf("take-in: the revision at %d is validated by the ask %s (try %d); it waits for its end", v.Seq, ask.ID, v.Try)
+	return nil
+}
+
+// revisionHead is the revision's head of repository: the newest merge of it the revision covers, else the commit its entry stands at.
+func revisionHead(ready []PendingEntry, repository, commit string) string {
+	var seq uint64
+	head := commit
+	for _, e := range ready {
+		if e.Forge.Merge != "" && strings.EqualFold(e.Forge.Repository, repository) && e.Value.Seq >= seq {
+			seq, head = e.Value.Seq, e.Forge.Merge
+		}
+	}
+	return head
+}
+
+// writeValidation writes v on ready[n] and takes it from every other value, each by compare-and-set; a new validation clears the
+// value's refusal. A value lost under it is an error: the evaluation is made again.
+func (ix *Indexer) writeValidation(ctx context.Context, ready []PendingEntry, n int, v *takein.Validation, own string) error {
+	for i, e := range ready {
+		if i != n && e.Value.Validation == nil {
+			continue
+		}
+		p := e.Value
+		p.Validation, p.LastWriter = nil, own
+		if i == n {
+			p.Validation, p.Refused = v, ""
+		}
+		data, err := encodePending(p)
+		if err != nil {
+			return err
+		}
+		if err := ix.Pending.Update(ctx, e.Key, data, e.Revision); err != nil {
+			return fmt.Errorf("%s.%s: %w", PendingState, e.Key, err)
+		}
+	}
+	return nil
+}
+
+// sayValidation says the revision's wait in take-in.pending with its refusal or why it could not validate.
+func (ix *Indexer) sayValidation(ctx context.Context, ready []PendingEntry, v *takein.Validation) {
+	t := revisionWait(takein.TakeInPending, ready, "")
+	t.Failed = v.Failed
+	t.Refused = ready[newestOfRevision(ready)].Value.Refused
+	ix.sayTakeIn(ctx, t)
+}
+
+// errNoValidationAnswer is an end whose answer is no verdict of both cases.
+var errNoValidationAnswer = errors.New("no answer")
+
+// HearValidationEnded takes in the end of a validation ask (§713), heard on the build seat's step-ended through the indexer's own
+// durable consumer: only an end of the indexer's asks outside a pipeline; an end whose ask no pending value names now is dropped,
+// written in the journal. The answer is read from the event's own output or output object (A-247).
+func (ix *Indexer) HearValidationEnded(ctx context.Context, e buildstep.StepEnded) error {
+	if e.Asker != ValidationAsker || e.Pipeline != "" || e.Ask == "" || ix.Pending == nil || !ix.pendingOnBus(ctx) {
+		return nil
+	}
+	own := ix.ownBuildNow(ctx)
+	ix.pendingMu.Lock()
+	defer ix.pendingMu.Unlock()
+	entries, err := ReadPending(ctx, ix.Pending, ix.logf)
+	if err != nil {
+		return err
+	}
+	ready := WaitsOf(entries).Ready
+	n := -1
+	for i, p := range ready {
+		if p.Value.Validation != nil && p.Value.Validation.Ask == e.Ask {
+			n = i
+		}
+	}
+	if n < 0 {
+		ix.logf("take-in: the end of the validation ask %s (%s on %s) is dropped: no pending revision names that ask now", e.Ask, e.Outcome, e.Node)
+		return nil
+	}
+	ready, lost, _, _ := ix.loadNewest(ctx, ready)
+	if len(lost) > 0 {
+		return fmt.Errorf("the revision the validation ask %s ended for holds a merge that cannot be read", e.Ask)
+	}
+	n = newestOfRevision(ready)
+	v := *ready[n].Value.Validation
+	refused, failed := ix.validationAnswer(ctx, ready, e, v)
+	p := ready[n].Value
+	switch {
+	case failed != "":
+		v.Failed = failed
+	case refused != "":
+		p.Refused = refused
+	default:
+		v.Accepted = v.Seq
+	}
+	p.Validation, p.LastWriter = &v, own
+	data, err := encodePending(p)
+	if err != nil {
+		return err
+	}
+	if err := ix.Pending.Update(ctx, ready[n].Key, data, ready[n].Revision); err != nil {
+		return fmt.Errorf("%s.%s: %w", PendingState, ready[n].Key, err)
+	}
+	if v.Accepted == 0 {
+		ready[n].Value = p
+		ix.sayValidation(ctx, ready, &v)
+		ix.logf("take-in: the validation ask %s of the revision at %d ended: refused %q, could not validate %q", e.Ask, v.Seq, refused, failed)
+		return nil
+	}
+	ix.logf("take-in: the validation ask %s accepted the revision at %d", e.Ask, v.Seq)
+	if own == "" {
+		return nil // the take-in waits for the build this program runs, as every take-in does
+	}
+	_, _, err = ix.evaluate(ctx, own, false)
+	return err
+}
+
+// validationAnswer reads the end's answer: the refusal of the revision, or why it could not validate (the step did not pass, the
+// program exited other than 0, its answer is no verdict of both cases, or its request is no longer the one asked).
+func (ix *Indexer) validationAnswer(ctx context.Context, ready []PendingEntry, e buildstep.StepEnded, v takein.Validation) (string, string) {
+	if e.Outcome != buildstep.OutcomePassed {
+		return "", strings.TrimSpace(e.Outcome + ": " + e.Said)
+	}
+	out := []byte(e.Output)
+	if len(out) == 0 && e.OutputObject != "" {
+		if ix.ReadStepOutput == nil {
+			return "", "the answer is in the output object " + e.OutputObject + ", which this indexer does not read"
+		}
+		var err error
+		if out, err = ix.ReadStepOutput(ctx, e.OutputObject); err != nil {
+			return "", "the output object " + e.OutputObject + " could not be read: " + err.Error()
+		}
+	}
+	var answer buildstep.RunAnswer
+	if err := json.Unmarshal(out, &answer); err != nil {
+		return "", fmt.Sprintf("the run's answer is no run answer: %v", err)
+	}
+	if answer.Exit != 0 {
+		return "", fmt.Sprintf("the manifest validator exited %d: %s", answer.Exit, answer.Said)
+	}
+	var verdict composer.Verdict
+	if err := json.Unmarshal(answer.Output, &verdict); err != nil {
+		return "", fmt.Sprintf("%v: the manifest validator's output is no verdict: %v", errNoValidationAnswer, err)
+	}
+	req, _, err := ix.validationRequest(ctx, branchOfRevision(ready), ready)
+	var raw []byte
+	if err == nil {
+		raw, err = json.Marshal(req)
+	}
+	if err != nil {
+		return "", "the request cannot be made again to read the verdict: " + err.Error()
+	}
+	if runDigest(raw) != v.Input {
+		return "", "the revision's request is no longer the one the ask " + v.Ask + " was asked with"
+	}
+	refused, err := ValidationRefusal(req, verdict)
+	if err != nil {
+		return "", err.Error()
+	}
+	return RefusedWords(refused), ""
+}
+
+// ValidateAgainTool asks the validation of a revision that could not validate again by hand (§713).
+const ValidateAgainTool = "indexer_validate_again"
+
+// validationWords is the validation's state as the hand ask answers it.
+func validationWords(v *takein.Validation, refused string) string {
+	switch {
+	case v == nil:
+		return "no validation is asked yet"
+	case v.Accepted != 0:
+		return fmt.Sprintf("accepted at %d (try %d, the ask %s)", v.Accepted, v.Try, v.Ask)
+	case v.Failed != "":
+		return fmt.Sprintf("could not validate at %d (try %d): %s", v.Seq, v.Try, v.Failed)
+	case refused != "":
+		return fmt.Sprintf("refused at %d (try %d): %s", v.Seq, v.Try, refused)
+	default:
+		return fmt.Sprintf("the ask %s is out since %s (try %d at %d)", v.Ask, v.Asked.UTC().Format(time.RFC3339), v.Try, v.Seq)
+	}
+}
+
+// ValidateAgainByHand is indexer_validate_again answered (§713): the ready revision under key (its oldest merge's m. key, as
+// indexer_pending names it) whose validation could not validate is asked again, the next try; its answer says the ask's state.
+// A revision accepted, refused or whose ask is out is asked nothing: a refusal is asked again only by a later merge of its branch.
+func (ix *Indexer) ValidateAgainByHand(ctx context.Context, key, by, why string) TakenIn {
+	r := TakenIn{Module: key}
+	if ix.Pending == nil || ix.ValidationAsks == nil {
+		r.Answer = "this indexer asks no validation: nothing asked"
+		return r
+	}
+	own := ix.ownBuildNow(ctx)
+	ix.pendingMu.Lock()
+	defer ix.pendingMu.Unlock()
+	entries, err := ReadPending(ctx, ix.Pending, ix.logf)
+	if err != nil {
+		r.Answer = err.Error()
+		return r
+	}
+	ready := WaitsOf(entries).Ready
+	if len(ready) == 0 || ready[0].Key != key {
+		r.Answer = fmt.Sprintf("no revision waits under %s: indexer_pending names the waits", key)
+		return r
+	}
+	ready, lost, reasons, _ := ix.loadNewest(ctx, ready)
+	if len(lost) > 0 {
+		r.Answer = fmt.Sprintf("nothing asked: the message of %s is not read (%s)", lost[0].Key, reasons[lost[0].Key])
+		return r
+	}
+	newest := ready[newestOfRevision(ready)]
+	v := newest.Value.Validation
+	if v == nil || v.Seq != newest.Value.Seq || v.Failed == "" {
+		r.Answer = "nothing asked: the validation is " + validationWords(v, newest.Value.Refused) + "; only one that could not validate is asked again by hand"
+		return r
+	}
+	ix.logf("take-in: the validation of %s is asked again by hand by %s: %s", key, by, why)
+	if err := ix.askValidation(ctx, ready, own); err != nil {
+		r.Answer = "the validation was not asked again: " + err.Error()
+		return r
+	}
+	after, err := ReadPending(ctx, ix.Pending, ix.logf)
+	if err == nil {
+		ready = WaitsOf(after).Ready
+	}
+	if err != nil || len(ready) == 0 {
+		r.Answer = "asked again; its state is not read back"
+		return r
+	}
+	n := ready[newestOfRevision(ready)]
+	r.Stored = n.Value.Validation != nil && n.Value.Validation.Failed == ""
+	r.Answer = fmt.Sprintf("asked again by %s (%s): the validation is %s", by, why, validationWords(n.Value.Validation, n.Value.Refused))
+	return r
+}
diff --git a/modules/mesh-delivery-indexer/internal/index/validation_wait_test.go b/modules/mesh-delivery-indexer/internal/index/validation_wait_test.go
new file mode 100644
index 00000000..bc749e59
--- /dev/null
+++ b/modules/mesh-delivery-indexer/internal/index/validation_wait_test.go
@@ -0,0 +1,113 @@
+package index
+
+import (
+	"context"
+	"encoding/json"
+	"strings"
+	"testing"
+
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-indexer/takein"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-sdk/buildstep"
+	"git.novox.be/novox/mesh-delivery/modules/mesh-delivery-sdk/composer"
+)
+
+type askRecorder struct{ asks []buildstep.StepAsk }
+
+func (r *askRecorder) Put(_ context.Context, a buildstep.StepAsk) error {
+	r.asks = append(r.asks, a)
+	return nil
+}
+
+// Design 47 G §713, A-247: a pending revision names its ask on its newest value and resumes on that ask's end; an end of a
+// replaced ask is dropped; a run that could not validate is no refusal and never passed; the start asks nothing again while
+// the ask is out.
+func TestAPendingRevisionWaitsForItsValidation(t *testing.T) {
+	ctx := context.Background()
+	b := newTakeInBed(t)
+	asks := &askRecorder{}
+	b.ix.ValidationAsks, b.ix.Inputs, b.ix.Revisions = asks, newMem(), newMemObjects(0)
+	// No entry of the revision claims the seat mesh-catalog: the validation could not be asked, so it is failed, said, and
+	// nothing is taken in.
+	b.arrive(t, 2, b.merge(21, sha('c'), "tree-avahi-3", ""))
+	entries := readPending(t, b)
+	if len(entries) != 1 || entries[0].Value.Validation == nil || !strings.Contains(entries[0].Value.Validation.Failed, "claims the seat mesh-catalog") || len(asks.asks) != 0 {
+		t.Fatalf("pending %+v, asks %d: want m.2 pending with failed and no ask", entries, len(asks.asks))
+	}
+	if last := b.said[len(b.said)-1]; last.Kind != takein.TakeInPending || last.Failed == "" || last.Refused != "" {
+		t.Errorf("said %+v, want take-in.pending naming failed, never a refusal", last)
+	}
+	if w := PendingWaits(entries); len(w) != 1 || w[0].Validation == nil || w[0].Validation.Try != 1 {
+		t.Errorf("indexer_pending %+v, want the validation whole", w)
+	}
+	// An ask out: the newest value names it; the start asks nothing new while it is out.
+	loaded, _, _, _ := b.ix.loadNewest(ctx, entries)
+	req, _, err := b.ix.validationRequest(ctx, TrunkBranch, loaded)
+	if err != nil {
+		t.Fatal(err)
+	}
+	raw, _ := json.Marshal(req)
+	setValidation := func(v takein.Validation) {
+		e := readPending(t, b)[0]
+		p := e.Value
+		p.Validation = &v
+		data, _ := encodePending(p)
+		if err := b.pending.Update(ctx, e.Key, data, e.Revision); err != nil {
+			t.Fatal(err)
+		}
+	}
+	setValidation(takein.Validation{Ask: "mvl0frv18d1957", Input: runDigest(raw), Seq: 2, Try: 2})
+	if _, _, err := b.ix.TakeInAtStart(ctx); err != nil || len(asks.asks) != 0 || len(b.keys()) != 1 {
+		t.Fatalf("the start: %v, asks %d, pending %v: want it waiting for its ask", err, len(asks.asks), b.keys())
+	}
+	end := func(ask, outcome, said string, answer any) buildstep.StepEnded {
+		out, _ := json.Marshal(answer)
+		return buildstep.StepEnded{Ask: ask, ID: ask, Asker: ValidationAsker, Node: "ace", Outcome: outcome, Said: said, Output: string(out)}
+	}
+	verdict, _ := json.Marshal(composer.Verdict{Cases: []composer.CaseVerdict{{Name: "change"}, {Name: "trunk"}}})
+	accepted := buildstep.RunAnswer{Built: true, Exit: 0, Output: verdict}
+	// The end of a replaced ask is dropped, written in the journal.
+	if err := b.ix.HearValidationEnded(ctx, end("mvl0frv18d1950", buildstep.OutcomePassed, "", accepted)); err != nil || len(b.keys()) != 1 || !strings.Contains(b.logs.String(), "is dropped") {
+		t.Fatalf("a replaced ask's end: %v, pending %v", err, b.keys())
+	}
+	// could not run: pending with failed, never passed.
+	if err := b.ix.HearValidationEnded(ctx, end("mvl0frv18d1957", buildstep.OutcomeCouldNotRun, "no build node", nil)); err != nil {
+		t.Fatal(err)
+	}
+	if v := readPending(t, b)[0].Value.Validation; v == nil || v.Failed != "could not run: no build node" || v.Accepted != 0 {
+		t.Fatalf("after could not run: %+v", v)
+	}
+	// indexer_validate_again (§713): its hand act recorded first, then the next try asked; the answer says the ask's state.
+	var recorded []string
+	tools := ValidationTools(func(key string, value []byte) (TakeInAsk, error) {
+		a, err := DecodeTakeIn(value)
+		if err != nil || key != "pending.validate-again."+takein.PendingKey(2) || !a.ValidateAgain {
+			t.Fatalf("asked %s %+v %v", key, a, err)
+		}
+		r := b.ix.ValidateAgainByHand(ctx, a.Pending, a.By, a.Why)
+		a.Result = &r
+		return a, nil
+	}, b.ix.now, func(what, why string) error { recorded = append(recorded, what); return nil })
+	if len(tools) != 1 || tools[0].Name != ValidateAgainTool {
+		t.Fatalf("tools = %v", tools)
+	}
+	if _, err := tools[0].Run(map[string]any{"key": takein.PendingKey(2)}); err == nil || len(recorded) != 0 {
+		t.Fatalf("asked again with no why: %v, %v", err, recorded)
+	}
+	got, err := tools[0].Run(map[string]any{"key": takein.PendingKey(2), "why": "the build node is back"})
+	if v := readPending(t, b)[0].Value.Validation; err != nil || len(recorded) != 1 || v == nil || v.Try != 3 || v.Failed == "could not run: no build node" ||
+		!strings.Contains(got.(*TakenIn).Answer, "try 3") {
+		t.Fatalf("asked again: %v, recorded %v, validation %+v, answer %+v: want the try after 2 asked", err, recorded, v, got)
+	}
+	setValidation(takein.Validation{Ask: "mvl0frv18d1959", Input: runDigest(raw), Seq: 2, Try: 3})
+	if r := b.ix.ValidateAgainByHand(ctx, takein.PendingKey(2), "lead", "again"); r.Stored || !strings.Contains(r.Answer, "is out") || readPending(t, b)[0].Value.Validation.Try != 3 {
+		t.Fatalf("an ask out was asked again: %+v", r)
+	}
+	// Asked again (by hand or by a later merge) and accepted: the revision is taken in, and its keys go.
+	setValidation(takein.Validation{Ask: "mvl0frv18d1958", Input: runDigest(raw), Seq: 2, Try: 3})
+	if err := b.ix.HearValidationEnded(ctx, end("mvl0frv18d1958", buildstep.OutcomePassed, "", accepted)); err != nil {
+		t.Fatal(err)
+	}
+	if len(b.keys()) != 0 || b.commit(t, "avahi") != sha('c') {
+		t.Fatalf("accepted: pending %v %+v, avahi at %s: want it taken in\n%s", b.keys(), readPending(t, b)[0].Value, b.commit(t, "avahi"), b.logs.String())
+	}
+}
diff --git a/modules/mesh-delivery-indexer/manifest_test.go b/modules/mesh-delivery-indexer/manifest_test.go
index 2eba8cea..677d57e3 100644
--- a/modules/mesh-delivery-indexer/manifest_test.go
+++ b/modules/mesh-delivery-indexer/manifest_test.go
@@ -179,7 +179,9 @@ func TestManifestDeclarations(t *testing.T) { // 1238/AC1, 1444 (reads the build
 	// Three invokes: the file of a registered module's manifest and lock files (registered.go), the forge's trees (the named paths' objects, since the indexer is the one reader of a manifest's paths:
 	// ADR 0499 clauses 2 and 3, ADR 0495 clause 1; and the module directories of the trunk, issue 1900) and whether a
 	// commit is in another (issue 1900).
-	if want := []string{"seat:git.trees", "seat:git.file", "seat:git.contains", "seat:git.open-pulls", "seat:git.branch", "mesh-delivery-forge-bridge.bridge_merged_message", "seat:node-engine.composition", "seat:mesh-delivery.source", "seat:mesh-module-assigner.assignments", "seat:mesh-module-assigner.placement", "seat:mesh-hand-acts.hand-act", "seat:mesh-watchdogs.presence", "seat:node-build-go.steps", "seat:node-build-node.steps", "seat:node-build-image.steps", "mesh-delivery-builder.builder_versions"}; !reflect.DeepEqual(m.Invokes, want) {
+	if want := []string{"seat:git.trees", "seat:git.file", "seat:git.contains", "seat:git.open-pulls", "seat:git.branch", "mesh-delivery-forge-bridge.bridge_merged_message", "seat:node-engine.composition", "seat:mesh-delivery.source", "seat:mesh-module-assigner.assignments", "seat:mesh-module-assigner.placement", "seat:mesh-hand-acts.hand-act", "seat:mesh-watchdogs.presence", "seat:node-build-go.steps",
+		"seat:node-build-go.accept.check", // design 47 G A-231: the validation's run ask (§712) on the check queue
+		"seat:node-build-node.steps", "seat:node-build-image.steps", "mesh-delivery-builder.builder_versions"}; !reflect.DeepEqual(m.Invokes, want) {
 		t.Errorf("invokes = %v, want %v", m.Invokes, want)
 	}
 	// 1945: indexer_take_in, served by its tools bundle through the takeins state; the process serves none. The same bundle
@@ -202,8 +204,9 @@ func TestManifestDeclarations(t *testing.T) { // 1238/AC1, 1444 (reads the build
 		// milestone 47/G W4.12 (design 47, the indexer's tools): the catalog graph revisions read and steered.
 		index.CatalogRevisionTool, index.CatalogRevisionsTool, index.CandidateGraphsTool, index.RecomputeTool, index.DropCandidateGraphTool,
 		index.EntryIndexTool, index.NamedDropTool, // design 47 G §675
-		index.ProposalsTool, index.ProposalDropTool, index.SeedAgainTool, index.InputsTool, index.PinsTool, index.UnpinTool, index.ConsumerTool, index.RunsTool, index.RunDropTool) // design 47 G §667, §8, §579, §64 (A-194)
-	if !reflect.DeepEqual(m.Tools, want) || len(want) != 49 || slices.Contains(m.Tools, "modules") {
+		index.ProposalsTool, index.ProposalDropTool, index.SeedAgainTool, index.InputsTool, index.PinsTool, index.UnpinTool, index.ConsumerTool, index.RunsTool, index.RunDropTool, // design 47 G §667, §8, §579, §64 (A-194)
+		index.ValidateAgainTool) // design 47 G §713
+	if !reflect.DeepEqual(m.Tools, want) || len(want) != 50 || slices.Contains(m.Tools, "modules") {
 		t.Errorf("tools = %v, want %v", m.Tools, want)
 	}
 	// Design 47 G §2, §9: every version of every registration is kept with no age limit, 64 MiB, on the old streams section.
diff --git a/modules/mesh-delivery-indexer/module.json b/modules/mesh-delivery-indexer/module.json
index 6041744f..26fdb649 100644
--- a/modules/mesh-delivery-indexer/module.json
+++ b/modules/mesh-delivery-indexer/module.json
@@ -75,7 +75,8 @@
     "indexer_unpin",
     "indexer_consumer",
     "indexer_runs",
-    "indexer_run_drop"
+    "indexer_run_drop",
+    "indexer_validate_again"
   ],
   "consumes": [
     "go-package-registry.published",
@@ -174,6 +175,7 @@
     "seat:mesh-hand-acts.hand-act",
     "seat:mesh-watchdogs.presence",
     "seat:node-build-go.steps",
+    "seat:node-build-go.accept.check",
     "seat:node-build-node.steps",
     "seat:node-build-image.steps",
     "mesh-delivery-builder.builder_versions"
diff --git a/modules/mesh-delivery-indexer/takein/takein.go b/modules/mesh-delivery-indexer/takein/takein.go
index cc3570d5..056b521f 100644
--- a/modules/mesh-delivery-indexer/takein/takein.go
+++ b/modules/mesh-delivery-indexer/takein/takein.go
@@ -141,6 +141,9 @@ type TakeIn struct {
 	// the seat definitions the revision carries (ADR 0633 §1), the manifest validator's problems. The revision waits for
 	// an indexer whose manifest is accepted, and says why here, as it says what it lost.
 	Refused string `json:"refused,omitempty"`
+	// Failed is why the revision's validation could not validate (design 47 G §713): the build seat's words, never a refusal
+	// and never passed; it is asked again by a later merge of the branch and by indexer_validate_again.
+	Failed string `json:"failed,omitempty"`
 	// Unknown is why the indexer holds a merge it does not take in although no indexer build is named: it cannot learn the build
 	// it runs itself (ADR 0633 §1), so Since is when it began not to know. A pending revision names WaitsFor or Unknown.
 	Unknown string `json:"own-build-unknown,omitempty"`
@@ -172,8 +175,8 @@ func (t TakeIn) check() error {
 		if !strings.HasPrefix(t.Key, "m.") {
 			return fmt.Errorf("delivery: a revision's take-in key is its oldest merge's m.<sequence>, not %q", t.Key)
 		}
-		if t.Kind == TakeInPending && t.WaitsFor == "" && t.Unknown == "" && len(t.Lost) == 0 {
-			return fmt.Errorf("delivery: a pending revision %s names the indexer build it waits for, why the indexer does not know its own, or the merges it lost", t.Key)
+		if t.Kind == TakeInPending && t.WaitsFor == "" && t.Unknown == "" && len(t.Lost) == 0 && t.Refused == "" && t.Failed == "" {
+			return fmt.Errorf("delivery: a pending revision %s names the indexer build it waits for, why the indexer does not know its own, the merges it lost, its refusal or why it could not validate", t.Key)
 		}
 	case TakeInGroup:
 		if t.Group == "" {
@@ -248,6 +251,21 @@ type PendingWait struct {
 	Unread []string `json:"unread,omitempty"`
 	// Refused is why the manifest of the indexer it names was refused (TakeIn.Refused).
 	Refused string `json:"refused,omitempty"`
+	// Validation is the revision's validation whole, as its newest pending value keeps it (design 47 G §713, A-247).
+	Validation *Validation `json:"validation,omitempty"`
+}
+
+// Validation is a pending revision's validation (design 47 G §712, §713, A-232, A-247), kept on the revision's newest pending
+// value alone: the run ask's id, when it was asked, its input's digest, the sequence of the newest merge it covers and the try
+// number for it, why it could not validate, and the sequence it was accepted at (never asked again once set).
+type Validation struct {
+	Ask      string    `json:"ask,omitempty"`
+	Asked    time.Time `json:"asked,omitzero"`
+	Input    string    `json:"input,omitempty"`
+	Seq      uint64    `json:"seq"`
+	Try      int       `json:"try"`
+	Failed   string    `json:"failed,omitempty"`
+	Accepted uint64    `json:"accepted,omitempty"`
 }
 
 // PendingAnswer is indexer_pending's answer: every wait, oldest first, and the pending keys that do not read.
diff --git a/modules/mesh-delivery-indexer/takein/takein_test.go b/modules/mesh-delivery-indexer/takein/takein_test.go
index 8d971c64..f69c1e49 100644
--- a/modules/mesh-delivery-indexer/takein/takein_test.go
+++ b/modules/mesh-delivery-indexer/takein/takein_test.go
@@ -22,6 +22,9 @@ func sampleTakeIns(since time.Time) []TakeIn {
 		{Kind: TakeInTaken, Key: PendingKey(12), What: TakeInRevision, Merges: m, WaitsFor: "src2:abc", Since: since,
 			By: "lead-47@shanks", Why: "the named indexer can never run"},
 		{Kind: TakeInPending, Key: PendingKey(13), What: TakeInRevision, Merges: m, Unknown: "the engine does not answer", Since: since}, // the indexer cannot learn its own build
+		// design 47 G §713: a revision refused by its validation, and one that could not validate.
+		{Kind: TakeInPending, Key: PendingKey(14), What: TakeInRevision, Merges: m, Refused: "a: names no version", Since: since},
+		{Kind: TakeInPending, Key: PendingKey(15), What: TakeInRevision, Merges: m, Failed: "could not run: no build node", Since: since},
 	}
 }